Defined as a dilated aorta more than150% greater than its normal diameter.
More than 4.5 cm in diameter is considered a thoracic aneurysm.
Ascending thoracic aortic aneurysms involve dilation of the aortic root and/or ascending aorta extending into the proximate aortic are.and affects approximately 5.3 per hundred thousand individuals per year worldwide.
Ascending thoracic aortic aneurysms are asymptomatic in approximately 95% of patients at presentation, and 5% have non-specific symptoms, such as chest pain, back pain, dysphagia or dyspnea.
May affect the ascending, arch or descending thoracic aorta.
Ascending thoracic aneurysms may expand without symptoms and cause they aortic rupture, which is associated with a mortality rate greater than 90%.
Approximately 25% of such patients have a concomitant abdominal aortic aneurysm.
Most frequently from degeneration of the media of the aortic wall.
There is an increase in incidence of thoracic aortic aneurysm, which is commonly an incidental finding on imaging studies form for various reasons.
Degeneration of the media leads to cystic medial necrosis with damage to the collagen, and elastin with smooth muscle cell loss, and increased ground substance in the medial layer.
The ascending aorta is most affected by cystic medial necrosis.
The descending thoracic aneurysms are related primary due to atherosclerosis.
Many patients have mutations in the gene responsible for lipoprotein abnormality found in Marfan’s syndrome but don’t have the Marfan’s syndrome.
Patients with ascending thoracic aortic aneurysm, should be evaluated for connective tissue disorders, family history of bicuspid valve, aortic aneurysm, and sudden death.
Evaluation for ascending thoracic aortic aneurysms include left ventricular function, aortic valve, root, and proximal ascending aorta and EKG gated aortic CT angiogram with contrast.
A thoracic aorta MRA is an alternative to CT and has a similar sensitivity of 98 to 100% and specificity of about 98% for aneurysm detection.
Up to 75% of patients with a bicuspid aortic valve have evidence of cystic medial necrosis.
The incidence of ascending aortic thoracic aneurysm is increased taming individuals with bicuspid aortic valve, which has a worldwide prevalence of 1 to 2%, and among individuals with a history of aortic dissection, familial connective tissue disorders syndrome.
Thoracic aortic ascending aneurysms also occur because of syphilis rheumatic diseases such as rheumatoid arthritis or Takayasu disease, but are rare.
Bicuspid aortic valve in patients younger than 30 years, have a dilated aortic diameter greater than expected based on age, sex, and body surface area up to 56% of cases.
Patients with bicuspid aortic valve have approximately nine fold increased risk for aortic dissection.
Thoracic aneurysm-inherited forms of medial degeneration are associated with defects in genes for fibrillin.
Inherited forms of medial degeneration are associated with defects in genes for fibrillin.
The onset of symptoms may indicate an expanding thoracic aortic aneurysm, with eminent serious complications such as dissection and rupture.
Surgical intervention is indicated for a symptomatic thoracic aortic aneurysm to minimize complications, regardless of the diameter of the aneurysm.
Treatment of asymptomatic thoracic aortic aneurysm involves weighing the risk of complications with expanding thoracic aortic aneurysm against the risk of prophylactic surgical intervention.
Patients with ascending thoracic aortic aneurysm blood pressure should be less than 130/80 mm of mercury.
For patients with a bicuspid aortic valve who have ascending aortic diameter of 5.0cm or greater should undergo surgery to replace the aortic root and the ascending aorta.
Other surgical indications include ascending aortic diameter 5 cm are greater with the risk factors of aortic dissection such as family history of aortic dissection, rapid growth rate of greater than .3 cm per year, preconception in women with bicuspid aortic valve and aortic diameter of 5 centimeters or greater.
Presently the cut off guideline for prophylactic surgical intervention in patients with asymptomatic thoracic aneurysm of based on observational studies and is not definitive.
In a study of elective thoracic aortic aneurysm repair repair it was found there was a lower in hospital mortality and morbidity compared to when there is a clinical presentation of an aneurysm associated acute aortic syndrome (Elbadawi,A).
surgical repair includes replacement of aneurysmal tissue with a polyester fiber.
For patients with ascending thoracic aneurysm and bicuspid aortic valve stenosis, aortic replacement is recommended.
Surgery can be performed frequently with minimally invasive procedures.
The five years survival rate after ascending artery root replacement is almost 90%.